The purpose of this study is to investigate the endocrine effect of infection and illness. In an infection a product of bacteria, called endotoxin, interacts with the body's defense mechanisms. The aim of this study is to discover how endotoxin stimulates the adrenal glands. Endotoxin is an experimental drug which is being used to test endocrine function. Three groups of subjects will be studied: healthy men, healthy premenopausal women and healthy postmenopausal women. Each subject will have a heparin lock inserted and blood will be withdrawn every 15 minutes for 8 hours. After 2 hours of a control period, endotoxin (4ng/kg) will be given intravenously. Hormones of the pituitary-adrenal axis and the pituitary axis will be measured.